1. Field of the Invention
The present invention relates to a camera arrangement having a camera connected to and aimed at a glass pane of a motor vehicle.
2. Background Art
DE 102 09 615 A1 (corresponding to U.S. Pat. No. 7,104,149) describes a camera arrangement having a camera connected to and aimed at a glass pane (e.g., a windshield) of a motor vehicle. A tube-like coupling element (“tube”) connects the camera to the glass pane. The space spanned by the tube between the camera and the glass pane is tightly sealed off from the external environment and hence has its own atmosphere, or is filled with a liquid “condensed medium”, to prevent the camera's field of view from being covered with dust or condensation.
This camera arrangement has disadvantages. First, sealing requires a relatively great deal of effort to maintain the impermeability of the tube over a desired service life. Second, the camera arrangement is not a self-contained module as the tube is filled or evacuated after the camera arrangement is installed on the glass pane. Third, as a result of the second disadvantage, installation and removal of the camera arrangement to and from the glass pane is relatively elaborate and laborious. Fourth, the space taken up by the camera arrangement is relatively large. This space is especially large if the glass pane has a high slope as the required enlargement of the volume of the tube further increases the sealing effort. Fifth, the relatively large space taken up by the camera arrangement causes relatively high reflection losses depending on the camera's viewing angle and the slope of the glass pane.
DE 102 37 554 A1 and DE 102 37 607 A1 describe similar camera arrangements without complete hermetic sealing of the tube. DE 102 37 608 A1 (corresponding to U.S. Pat. No. 6,799,904) describes features for eliminating the resulting condensation problems which occur with these camera arrangements. The features include an additional isolating air layer between the tube and the glass pane in the area of the camera's field of view. The air layer counteracts condensation in the camera's field of view. The camera arrangement described in DE 102 37 608 A1 is also without hermetic tube sealing. As such, assuming condensation and soiling can be avoided, this camera arrangement does not have the noted impermeability disadvantages. However, this camera arrangement still has the following disadvantages: a relatively large space requirement—especially with a high sloped glass pane; and relatively large reflection losses—depending on the viewing angle and the slope of the glass pane.